Interfacial separation between elastic solids with randomly rough surfaces: comparison of experiment with theory

We study the average separation between an elastic solid and a hard solid with a nominal flat but randomly rough surface, as a function of the squeezing pressure. We present experimental results for a silicon rubber (PDMS) block with a flat surface squeezed against an asphalt road surface. The theory shows that an effective repulse pressure act between the surfaces of the form p proportional to exp(-u/u0), where u is the average separation between the surfaces and u0 a constant of order the root-mean-square roughness, in good agreement with the experimental results.Comment: 6 pages, 10 figure

On the thermoelectricity of correlated electrons in the zero-temperature limit

The Seebeck coefficient of a metal is expected to display a linear temperature-dependence in the zero-temperature limit. To attain this regime, it is often necessary to cool the system well below 1K. We put under scrutiny the magnitude of this term in different families of strongly-interacting electronic systems. For a wide range of compounds (including heavy-fermion, organic and various oxide families) a remarkable correlation between this term and the electronic specific heat is found. We argue that a dimensionless ratio relating these two signatures of mass renormalisation contains interesting information about the ground state of each system. The absolute value of this ratio remains close to unity in a wide range of strongly-correlated electron systems.Comment: 15 pages, including two figure

Palynological evidence for environmental and climatic change in the lower Guadiana valley, Portugal, during the last 13 000 years

Pollen analysis of a 48 m AMS radiocarbon-dated sediment sequence from the Guadiana estuary provides the first record of Lateglacial and Holocene vegetation history in the Algarve province of Portugal. This paper focuses on the record of terrestrial pollen taxa, which document a series of forest expansions and declines during the period 13 000 cal. BP to 1600 cal. BP and provide insights into climate evolution in southwestern Iberia. The main vegetation phases identified in the Guadiana valley are (1) Lateglacial interstadial (Allerød) forest with Quercus and Pinus under a temperate, moist, continental climate; (2) a Younger Dryas forest decline (Quercus) and expansion of pinewoods, xeric scrub and open ground habitats (with Juniperus, Artemisia, Ephedra distachya type, Centaurea scabiosa type) under arid and cold conditions; (3) an early Holocene forest/scrub/open-ground vegetation mosaic developing under a warm, dry and continental climate; (4) a maximum of Quercus forest and thermomediterranean evergreen taxa (Olea, Phillyrea, Pistacia) reflecting a warm, moist oceanic climate between c. 9000 cal. BP and c. 5000 cal. BP; and (5) the expansion of shrublands with Cistaceae and Ericaceae under a drier climatic regime and increasing anthropogenic activity since c. 5000 cal. BP. Holocene episodes of maximum climatic aridity are identified in the record of xerophytic taxa (Juniperus, Artemisia, Ephedra distachya type) centred around 10 200 cal. BP, 7800 cal. BP, 4800 cal. BP, 3100 cal. BP and 1700 cal. BP. Regional comparisons suggest a correlation of arid phases across southern Iberia and northwest Africa, which can be related to abrupt North Atlantic coolings (Bond events).Research Council studentship for WJF (NERC/S/A/2001/06109), with the support of Trinity College and the Department of Geography, University of Cambridg

Emerging strategies for regeneration of historic urban sites:a systematic literature review

The importance and effectiveness of adaptive reuse as an alternative to the demolition of cultural heritage is well-studied. However, increasing demand in cities to redevelop larger scale urban historic sites requires new strategies to benefit from their inherent values. This paper focuses on strategies of regeneration for historic urban sites. The paper presents a systematic literature review of 45 papers, with case studies geographically concentrated in Europe and Asia, and a focus on residential, commercial, and industrial areas. From the case studies, 46 different regeneration strategies have been deduced. The various strategies are, via content analysis, dissected into a select number of drivers to find commonalities. These key drivers are user participation, top-down, genius loci, sustainability, and conversion. Based on the reflections of the reviewed authors, a performance evaluation assesses the outcomes of these strategies. Further data analysis is conducted at the level of individual drivers as well as their combinations to deduce the most positive-evaluated strategies. Findings show that genius loci contributes to the most positive-evaluated strategies, while top-down driven strategies contribute to the most negative-evaluated strategies. Furthermore, strategies are assessed positively when three or more drivers are considered regardless of their combination. This paper acts as a starting point for further research into the formation of regeneration strategies and into the specific drivers and their combinations or underlying relations. Moreover, it can be of contribution to the practice, to support decision makers and urban planners in developing the appropriate regeneration strategy for historic urban sites

Effects of amlodipine and lisinopril on left ventricular mass and diastolic function in previously untreated patients with mild to moderate diastolic hypertension

The aim of the study was to compare the effects of two long-acting antihypertensive agents, the calcium-antagonist amlodipine and the ACE inhibitor lisinopril, on left ventricular mass and diastolic filling in patients with mild to moderate diastolic hypertension from primary care centres. It is a 1-year prospective, double-blind, randomized, parallel group, comparative study. Patients between 25 and 75 years of age with untreated hypertension with elevated diastolic blood pressure (> or = 95 mmHg) on three occasions (twice on the first visit and once only on the second and third visits) were recruited from a population survey. After 4 weeks placebo run-in 71 patients were randomized to dosages of amlodipine 5-10 mg or lisinopril 10-20 mg, which were titrated on the basis of the effects on blood pressure. Fifty-nine patients completed the study period. Primary endpoints were left ventricular mass index and early to atrial peak filling velocity. Office and ambulatory blood pressure and other echocardiographic measurements were considered secondary. Decrease in blood pressure was equal for both treatment regimens. A statistically significant decrease in left ventricular mass index in both treatment groups was observed: -11.0 g/m2 (95% CI: -6.0, -16.1) in the amlodipine group and -12.6 g/m2 (95% CI: -8.2, -17.0) in the lisinopril group. The higher the baseline value of left ventricular mass before treatment, the more the decrease after treatment. Early to atrial peak filling velocity did not change significantly within the treatment groups: +0.07 (95% CI: -0.01, +0.15) in the amlodipine group and +0.01 (95% CI: -0.06, +0.08) in the lisinopril group. However, analysis of time measurements of the early peak showed significant changes for both treatment groups. No significant differences in primary and secondary endpoints between treatment groups were found. Twelve patients did not complete the study, seven in amlodipine and five in lisinopril, basically due to adverse events. The effects of amlodipine and lisinopril on left ventricular mass and early to atrial filling peak velocity after 1 year of treatment in patients with previously untreated mild to moderate hypertension are similar. Further studies are recommended, particularly with a larger sample size and a follow-up of longer duration. Record 24 of 32 - SilverPlatter MEDLINE(R

Modifying effect of dual antiplatelet therapy on incidence of stent thrombosis according to implanted drug-eluting stent type

Aim To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). Methods and results Of 8709 patients in PROTECT, 4357 were randomized to E-ZES and 4352 to C-SES. Aspirin was to be given indefinitely, and clopidogrel/ticlopidine for ≥3 months or up to 12 months after implantation. Main outcome measures were definite or probable stent thrombosis at 3 years. Multivariable Cox regression analysis was applied, with stent type, DAPT, and their interaction as the main outcome determinants. Dual antiplatelet therapy adherence remained the same in the E-ZES and C-SES groups (79.6% at 1 year, 32.8% at 2 years, and 21.6% at 3 years). We observed a statistically significant (P = 0.0052) heterogeneity in treatment effect of stent type in relation to DAPT. In the absence of DAPT, stent thrombosis was lower with E-ZES vs. C-SES (adjusted hazard ratio 0.38, 95% confidence interval 0.19, 0.75; P = 0.0056). In the presence of DAPT, no difference was found (1.18; 0.79, 1.77; P = 0.43). Conclusion A strong interaction was observed between drug-eluting stent type and DAPT use, most likely prompted by the vascular healing response induced by the implanted DES system. These results suggest that the incidence of stent thrombosis in DES trials should not be evaluated independently of DAPT use, and the optimal duration of DAPT will likely depend upon stent type (Clinicaltrials.gov number NCT00476957